If you're entering dates on an Excel worksheet, and there's data in the adjacent column, you can use the Fill handle to make the job quick and easy.
Enter the first date in the date column, then point to the Fill handle, and double-click.
That fills the dates down to the first blank cell in the adjacent column. The dates are entered in a series of 1 day intervals.
If you want all the dates the same, while the range of cells is still selected, press Ctrl+D on the keyboard. That's the keyboard shortcut for Fill Down, and it copies the date from the first cell, into all the selected cells below.
Watch the Video
To see the steps for filling the dates, you can watch this very short video. I created this with the latest version of Camtasia Studio, which has a new feature that captures keyboard shortcuts, and can show the key combinations in the video.